Advanced Materials Research Vol. 700

Abstract: Giant magnetostrictive transducer in the work show strong magnetic mechanical coupling characteristics and nonlinear characteristics, its magnetic state and mechanical state influence each other, coupling process is very complicated, this paper according to the giant magnetostrictive material features, combined with the magnetic domain theory, establish the super magnetostrictive micro displacement actuator model, Explore stress and magnetic field changes, GMM inner magnetic strength change, and the change of strain. Join based on giant magnetostrictive actuator structure and working principle, from the principle of physics, mathematics phenomenological theory Angle to establish the combination of the mathematical model of giant magnetostrictive actuator: According to the actuator output power and output displacement, combined with the equation of motion establish output displacement - output force model. According to an internal magnetic induction intensity change, establish actuator induction voltage model; According to J-A model magnetization model. By using the finite element theory and the Hamilton principle of minimum potential energy, energy conservation principle to this mathematical model, and analyze the result.

Abstract: The structure transition and electrocaloric effect in PbZr_1-xTi_xO₃ with x=0.5 and 0.6 were MV/m can make the structural transition be a continuous one. In addition, when x =0.5 and 0.6 at the zero field, the first order structural transition occurs at T₀=665 and 691 K, respectively. The first order structural transition comes to the second one upon the strong electric field, which leads to lower the change of specific hea. The structural transition temperature is shifted at high temperature with increasing electric field. The maximum electrocaloric effect is present at about 200 K above their corresponding Curie temperatures.

Abstract: Lithium-ion secondary cell has high energy density, stable and high working voltage, wide working temperature and long working term. It is a safe and clean energy resource without pollution. At present, Lithium Hexafluorophosphate is used as conducting electrolyte lithium salt in lithium-ion secondary batteries. But Lithium Hexafluorophosphate as conducting electrolyte lithium salt has some disadvantages such as hydrolysis and instability. Lithium Bis (heptafluoroisopropyl) t-etrafluorophosphate Li [(C₃F₇)₂PF₄] was received by simons process from diisopropylchlorophosphane in this paper. As electrolyte of Li ion secondary cell, Li [(C₃F₇)₂PF₄] had lower vapor pressure than LiPF₆ in the solvent in the same temperature, comparable conductivity and oxidation stability in the same concentration in room temperature. It was worth mentioning that Li [(C₃F₇)₂PF₄] has excellent stability towards hydrolysis. The synthesis process is safe and easily controlled.

Abstract: Prepare TiO₂ doped with ZnO or Fe₂O₃ composite photocatalytic film by using sol-gel method and characterize its microstructure and light absorption performance with X-ray diffraction instrument (XRD), scanning electron microscopy (SEM) and UV-visible spectrophotometer. The results show that: particles of TiO₂ doped with Fe₂O₃ composite photocatalytic film are uniform and well dispersed; the rough surface of the film has a certain gap which is helpful for the adhesion of gas and liquid; the diameter of the particles is about 50 nm. The crystal grain size of TiO₂ film doped with ZnO is bigger, about 100 nm; the gap of the film is less and particles are nearly spherical and protruding, the shape of grain is structured. The absorption spectrum of TiO₂ doped with ZnO or Fe₂O₃ has a red shift and both of their absorption intensity is higher than that of pure TiO₂ film in the scope of the ultraviolet and visible region.

Abstract: This study presents a simple technique for improving the power conversion efficiency of a AlGaAs-GaAs based solar cell. A traditional III-V semiconductor solar cell heterojunction structure, i.e. n-GaAs/n-AlGaAs/n-GaAs/i-GaAs/p-GaAs is used. The top n-GaAs/n-AlGaAs structure is responsible for the selective etching stop layer. The selective etched surface barriers associated with polymer gratings with different aspect ratios are produced on solar cell by using the photolithography and Micro Electro Mechanical Systems (MEMS) techniques. A reflective-type diffraction optical grating is fabricated on the surface of the solar cell to redirect the incident light reflected from the solar cell back onto the solar cell surface. The experimental results show that the addition of the optical grating increases the open circuit voltage, Voc, from 4.51 V to 4.73V and improves the maximum output voltage, V_m, from 4.12V to 4.32V. From inspection of surface reflectivity , the average reflectivity is also found to be 13.7% down to 9.9 %.

Abstract: Amorphous Ti_63.7Nb_21.3Zr_4.5Ta_1.5Fe₉ powder has been designed and fabricated by mechanical alloying (MA) from a mixture of pure titanium and other elemental powders under a purified argon gas atmosphere in a stainless steel vial together with stainless steel balls. The amorphous alloy powders were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that a transform from a well-developed dislocation substructure to a mixed nanocrystalline plus amorphous structure occurs in Ti_63.7Nb_21.3Zr_4.5Ta_1.5Fe₉ when milling time increases from 0 h to 15 h. Moreover, amorphous Ti_63.7Nb_21.3Zr_4.5Ta_1.5Fe₉ powders were prepared after mechanical milling for 40 h. The results obtained are of the most significance for future work of densification of the milled powders.

Abstract: Spray rolling is a novel metallic semi-solid near-net-shape forming technology. This paper describes the qualitative influence of the key process parameters on the nucleation temperature during gas horizontal atomization stage in the spray rolling of 7050 aluminum alloy. The Newtonian heat transfer formulation has been coupled with heterogeneous nucleation, as well as the special solidification process. Results show that the droplet diameter has remarkable influence on nucleation temperature during spray rolling of 7050 aluminum alloy compared with that of wetting angle. The nucleation temperature approximately is 878K.

Abstract: According to the G-P algorithm and using the MATLAB procedure, the paper carried on the analysis to the geochemical data with Material Properties of some mining area, and obtained the correlation dimension of this local mineral resource element. This result provided the quota basis for the minerals reasonable development.

Abstract: Due to the presence of recalcitrant organic compounds, the pulp and paper effluents after treatment by conventional biological processes still contain high concentration of chemical oxygen demand (COD) and colored substances and do not satisfy the national emission standard. The objectives of this work are to present the research process on environmental materials with application of ozone-based technologies in removal of characteristic pollutants in pulp and paper effluents and suggest the feasible development trend. In this work, basic mechanisms of degradation of organic pollutants by ozone-based technologies in the presence of environmental materials as catalyst are described. The removal efficiencies of characteristic pollutants commonly found in pulp and paper effluents, such as absorbable organic halogens (AOX), resin and fatty acids, phenolic compounds, lipophilic wood extractives and ethylenediaminetetraacetic acid (EDTA), are presented.